Absorbent for carbon dioxid in breathing apparatus for use in mine-rescue work or like purposes.



' I. ABsoEBEiv'r FOR cannon DIOXID 11v BREATHING APPARATUS on USE mMINE- v 7 1 223 244 Specification of Letters Patent.

No Drawing.

EDWARD JOHN aEveiv, E Lennon, ENGLAND.

RESCUE WORK OE'LIKE PUErosEs.

1 1T0 all whom it may concern."

I Be it known that'I, EDWARD J HN BEVAN, .asubject of the King of sidingin London, a certain new and useful Improved Absorbout for Carbon ratusforUse inMineRescue Work or like Great Britain, re-, England, haveinvented Dioxid in Breathing Appa- I Purposes, of which the followingisa specification.

In breathing apparatus, such as used 'n mine rescue work and for likepurposes, t e

. carbon dioxid exhaled is absorbed by caustic alkali. The forms inwhich the alkali, gen

' erally causticsoda,

" come very hot dur ng partly because'they dellquesce and then offerresistance to respiration.

tion of thealkali and could be overcome v the use of a previouslyhydrated alkali, such however, is

has commonly been used are not satisfactory, partly because they be- Thefirst obj ection is mainly due to the'high heat of hydraas a strongsolution ;v the-latter, as objectionable as the deliquesced alkalireferred to above. 9

-r-By the present invention theabsorption '-chamber of the apparatus ischarged with j ;a material made by grinding cellulose prefwirably-woodpulp, I p caustic alkali, preferablysoda. This matewith a strongsolution of rial is itself known as an mtermediate product 1n themanufacture of-vlscose, and one 7 method of preparing it consists inincorporating by means of an edge runner 3 lbs. of

i caustic soda liquor containing 1 lb. of caustic I Copies of thispatent may be obtained for soda with 2 lbs. of ground wood pulp; thematerial thus prepared resembles bread crumbs,.eXcept in' color. It wasnotlto be foreseen that this material would have special advantages asan absorbent in the kind of apparatus in question. These advantages theabsorption and i in breathing apparatus and similar purposes,

form of bread crumbs and consists of ground j .wood pulp saturated with150 per cent. of;

Patented Apr. 17, 1917. Application filed Novembei' 17, 1915. Serial No.61,993.

are that, since it contains the' alkali in a more or less completelyhydrated condition,

it does not become hot during the absorption; that it exposes, per unitweight, a'very large. surface coated with caustic soda, so that a given;bulk of it is a better absorbent and of much less weight than the samebulk of caustic soda in lumps or sticks; that it does not deliquesce;that it 'isveasy to handle.

In the last three respects, it also surpasses any mlneral materiahsuchas pumice, saturated with hydrated alkali.

Having thus described the said invention and the best means I know ofcarrying the same into practical effect, I claim 1. A material forabsorbing carbon dioxid in breathing apparatus for mine rescue work iand similar purposes, which material consists of cellulose saturatedwith hydrated caustic alkali.

2. A material for absorbing carbon dioxid and similar purposes, whichmaterial has ;;the form of bread crumbs and consists of cellulosesaturatedv with alkali.

hydrated causticfor mine rescue work A. material for absorbing carbondioxid" I in breathing apparatus for mine rescue work which material hasthe I its weight of caustic soda solution of 33 per cent. strength. i

,In testimony whereof I- have signed. my name to this specification inthe presence of two subscribing witnesses.

EDWARD JOHN-BEVAN.

Witnesses:

J osErH MILLARD, W. I. S. KERKAN.

